The timing of Mark Zuckerberg’s Facebook IPO could swell the payoff for some insiders by tens of thousands of dollars.

The 27-year-old Internet star, who famously launched his social networking site ahead of his aggrieved Harvard pals back in 2004, will, by filing to go public today or in the near future, help employees sell insider shares this year ahead of an expected jump in the capital gains tax in 2013.

By filing the paperwork today, Zuckerberg all but insures the regulatory review will be over and shares will begin trading before the end of June.

That means the six-month lock-up period — during which insiders can’t sell shares — will expire before Dec. 31.

Most people expect the Bush-era tax cuts to expire on Jan. 1 — and the capital gains tax to swell to as high as 25 percent from its current 15 percent.

For soon-to-be wealthy Facebookers in line to get, say, $5 million in stock and who want to sell $1 million of their booty, they could save $100,000 in taxes under the Bush rules, according to a calculation by The Post, thanks to Zuckerberg’s IPO timing.

The capital gains tax will soar next year unless Congress acts to stop it, said Micah Bloomfield, a New York tax lawyer.